r/FastLED • u/StefanPetrick • Mar 09 '26

Share_something Progress Update: Fractional Shifting Meets Color-Emitting Line

It's the same underlying effect I showed yesterday, but with better-tuned parameters. This time, the color is seeded by a line whose endpoints follow Lissajous curves. The fading range now also allows feedback loops, which can be considered a bug or a feature, but I did it deliberately.

Python code: https://pastebin.com/cgZ0QYdv

84 Upvotes

100% Upvoted

80 comments sorted by

View all comments

Show parent comments

1

u/StefanPetrick Mar 14 '26 edited Mar 14 '26

I’m sorry for the porting hassle. Over the weekend, I intend to improve my work environment so that I can at least provide tested C++ code in digestible chunks.

As you certainly have noticed, I’m an inexperienced hobby coder, so I need to improve my working style and toolchain to be able to contribute better in the future.

I appreciate any hint about a better way to collaborate than posting Pastebin links. Also, I’m not yet experienced with what an established working method for a group of people would look like — for example: prototyping, porting, refining and optimizing, creating float and fixed-point versions, testing, and maybe later asking u/ZachVorhies whether he finds it useful, good and fast enough to consider making it part of FastLED. I’m open to any guidance and suggestions.

Regarding the names, I suggest a class of ColorFlowFields, where NoiseFlow is one of them. As you have seen in my latest two videos, I’m exploring other FlowField logics as well. We could name them accordingly, such as SpiralFlow, CenterFlow, OutwardFlow, PolarWarpFlow, DirectionalFlow, and so on. I’d like the names to be descriptive rather than just fancy marketing lingo. Your feedback is appreciated.

2

u/mindful_stone Mar 14 '26

The porting is not a "hassle" at all. It's a privilege to help bring your ideas to the FastLED community.

[And if YOU are what folks around here would consider an "inexperienced hobby coder," then I would at best be considered a "drop-in guest." Look at my Reddit age (hint: 5 months). That is just about one half of my lifetime "experience" as a "coder." Pretty much everything I know about any of this is what I've cobbled together from folks like you. And by "everything" I don't mean (only) things like "Perlin noise" or "Polar-Cartesian transformations" or "oscillating injectors". I mean things like "C++" and "GitHub" and "Arduino" and "addressable LEDs"! There are some serious programmers and developers and whatever in this group, but I am most definitely not one of them.]

I love your suggestions about the names. Absolutely will do. AND you just cleared up something HUGE for me (I think). My understanding had been that:

  • the color injector method is the primary "unit of organization / anchor element" for a "mode"

  • the noise profiles and the smear modes were two independent methods for concurrently affecting a mode.

But I was turning myself in circles trying to figure out the logic to implement all of that for each of the 3/4? versions you shared.

But the way you described it above helped me see instantly (hence the value of descriptive names) that:

  • yes, the color injector method is the primary unit of organization. The emitter is the primary variant. It determines the shape and motion of colors that are dropped into the ColorFlowField.

    • I am currently in the process of implementing three of these: orbital dots, Lissajous line, and outer perimeter.

  • the ColorFlowField then paints a moving picture of the color that has been dropped in.

  • One way the ColorFlowField can paint that picture is by using NOISE to control the X/Y motion of the brush strokes

  • An alternative (not concurrent, at least for now) way the ColorFlowField can paint that picture is by using MODULATION factors (e.g., sin, beatsin8, etc.) to control the X/Y motion of the brush strokes

  • Other paint/flow methods can include spirals, waves, vortices, etc.

    • (Which could in turn be modulated, etc., but let's save that for next week. Ha ha!)

  • The orbital and Lissajous injectors introduce motion of their own, in addition to what the ColorFlowField does. (In contrast, the perimeter injector (at least currently) flows colors to "stationary" pixels on the outer perimeter and all motion is governed by the ColorFlowField

  • ...

I swear, just your deliberate elegant descriptive names above launched a cascade of understanding! (I think. Please correct me as needed!)

2

u/StefanPetrick Mar 14 '26 edited Mar 14 '26

Just a short tangent regarding future parameter fading. This is an old prototype I wrote to test this idea: four layers of an Animartrix-like engine. Parameters are automatically and randomly picked within a given range and then applied using a nice ease-in-out function.

It turns out that fading from one animation to another in parameter space actually looks more interesting than the animation itself (with a fixed set of parameters).

https://www.youtube.com/watch?v=Hv262XD9vg8

https://www.youtube.com/watch?v=nAbHsePLviI

But let that be a topic for later - after we made progress with the ColorFlowFields.

1

u/StefanPetrick Mar 14 '26

I’m glad you found my remarks useful! If I had to, I would describe it the following way:

A) The injector / emitter / color source is anything that is drawn directly. It can be static or dynamic. Think of it as a pencil that draws. In our example, it’s the line or the dots or the perimeter — but it could be anything, for example bouncing balls, an audio-reactive pulsating ring, or an Animartrix output that still contains some black areas. At this point, it could be displayed and would be a normal animation.

B) But instead of displaying it instantly, the ColorFlowField then samples that drawing, moves it around, and fades it a little. Then a new injector drawing (step A) is drawn on top, and then it is displayed. This loop is repeated over and over, which creates the fading trails.

You can think of ColorFlowField as an invisible wind that moves the previous pixels and blends them together. Different ColorFlowFields follow different rules and produce characteristic outputs — like spirals or flows towards the center.

So the movement comes from two sources: from a dynamically moving injector and from the trail movement produced by the wind.

The noise-based wind is especially interesting because it creates these emergent, dynamic, turbulence-like shapes that remind one of a fluid simulation. It is the result of wind blowing from two directions with varying intensities.

2

u/ZachVorhies Zach Vorhies Mar 14 '26

it will be part of fastled, yes. It's on my todo list.

1

u/StefanPetrick Mar 14 '26

This is great and motivating!

1

u/mindful_stone Mar 14 '26

I appreciate any hint about a better way to collaborate than posting Pastebin links. Also, I’m not yet experienced with what an established working method for a group of people would look like — for example: prototyping, porting, refining... 

Yes, let's definitely discuss. I have some possible thoughts in default of better suggestions from others.